Retrachydes thoracicus – times four!

Disclaimer—these are not great photos!

A few days ago I posted this little quip as my status on Facebook: “Cool! Found a Retrachydes thoracicus thoracicus on the sidewalk outside my hotel!” I chuckled a little as I posted it, knowing that only a select few who read it would know what the heck I was talking about (of course, a right click to select “Search with Google” reveals the answer instantly). Of course, it is a species of longhorned beetle (family Cerambycidae) that apparently is found commonly in South America. I wanted to take some photographs of the beetle to show those who didn’t do the Google search just what it looked like. Unfortunately, the beetle was already somewhat moribund when I found it, and no matter how much I coaxed and prodded it on the stick I placed it on, it just looked… well, dumb. Legs out of position, antennae hanging limply, and the beetle itself laying prostrate on the branch, as if it barely had the strength to hang on (which actually was the case). Shame—it sure is an attractive species, with its densely pubescent and transversely gibbous pronotum (obviously the source of its name) and striking orange-banded antennae. C’est la vie!

Lately I’ve been trying to get a better handle on choosing backgrounds when I photograph insects, no longer content with the often busy and distracting backgrounds that show up in photographs taken completely in situ. It’s often a simple matter to hold the object on which the insect is sitting in front of something that gives the desired background effect, and having this perfectly calm yet strikingly attractive beetle to work with seemed to invite experimentation. I’m also trying to get a better feel for how to use higher ISO settings to make it easier to get these various “non-black” backgrounds while still using flash to get acceptable depth of field with the subject itself. Below are four of the better shots that came out of the session (yes—sadly, these are the “better” ones). I’m loathe to go below 1/160 sec exposure because of motion blur and would like to keep aperture settings quite small, so fairly high ISO settings are required to get the background effects I’m looking for. I think I’ve learned that ISO 1000 is about as high as I can go before the background gets unacceptably noisy—at small sizes the photos look fine, but open them up larger size and you’ll see what I mean. Anyway, ignoring the composition and noise issues, which background do you like best?

ISO 1000, 1/160 sec, f/14 - cloudy sky background

ISO 1600, 1/160 sec, f/14 - pavement background (close)

ISO 1600, 1/160 sec, f/14 - pavement background (more distant)

ISO 1600, 1/160 sec, f/14 - pavement background (foliage)

Copyright © Ted C. MacRae 2012

14 thoughts on “Retrachydes thoracicus – times four!

  1. I liked the green and the blue backgrounds. I liked how these colors contrasted with the orange-brown of the beetle setting it apart. Though, I agree the blue does look a little unnatural like a microsoft plate color.

  2. Last night when I looked at your post on my phone in an otherwise dark room I liked the more distant pavement shot. Now, checking it on my computer in my bright office where I can more easily respond, I prefer the close pavement shot. I guess this goes to show that context affects preferences. I think the pavement backgrounds (not the foliage) complement the other colors in the shot. I agree the cloudy sky looks unnatural, like a grey card or something.

    • This brings up another issue I’ve been wondering about. I do most of my photo processing on the laptop rather than in the dock with the larger monitor (the life of a mobile person!). The laptop monitor is fairly large, but not nearly as large as the one in the docking station, and I sometimes worry that my processing isn’t optimized for best viewing.

  3. I’ll throw another vote in for the distant pavement! And I think you’re being a little tough on yourself regarding the photo quality; look good to me!

  4. I’ve gotten a little (too?) obsessed lately with blue sky backgrounds. I like them in the previous photos that I’ve shown but not this one – perhaps because there is no green foliage to compliment the blue.

    I think I like the last two best, though I’m not completely happy with either. With the distant pavement I could’ve eased up on the ISO (800 or 640) and stayed closer to the pavement to get the same effect, so that might be the trick. For the foliage, I just don’t like the busyness of the mottling, but that can be addressed by finding a larger leaf to serve as a backdrop.

  5. I personally prefer a background that resembles the habitat the insect would be found in, since the wrong background could be misleading. Here are my immediate gut reactions:

    Cloudy Sky — It looks like it’s in captivity or posed in a museum exhibit.
    1st Pavement — Xeric habitat.
    2nd Pavement — A bare trail or muddy bank, perhaps climbing to escape a flood.
    3rd Pavement (foliage) — Foliage, of course!

    Not knowing where this bycid usually hangs out, I like ‘foliage’ the best.

    • An excellent point – so obvious that I’m amazed I hadn’t even considered it!

      There are few native trees in this part of Argentina, but a beetle this wide ranging must be fairly indiscriminate in its choice of host trees. Also, given its size, it must breed in rather large trees. A large tree is a large tree whether in a forest, prairie, or desert, so sitting on a branch in front of foliage seems reasonable to me.

  6. I like the foliage background the most but the colors arent as pronounced. I had a quick question, why are you using an aperature of 14? do you use it for any macro photo or just these so the background wont be as out of focus? Thanks a lot.

    • Normally I’m shooting smaller subjects – f/13-16 gives good DOF at the sizes I’m normally dealing with. I could’ve gotten away with a lower f-stop with this big guy and created a softer background but didn’t think about it.


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